Breech block and firing mechanism therein



Jan. 1, 1952 w. SUMMERBELL' 2,580,433

BREECH BLOCK AND FIRING MECHANISM THEREIN Filed Dec. 4, 1946 6 Sheets-Sheet l William 5 ummer]: g 11 m 4 I dyg wyflwvx Wm 1952 w. SUMMERBELL BREECH BLOCK AND FIRING MECHANISM THEREIN 6 Sheets-Sheet 2 Filed Dec. 4, 1946 1 2 T m l. 0

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1952 w. SUMMERBELL 2,580,483

BREECH' BLOCK AND FIRING MECHANISM THEREIN Filed Dec. 4, 1946 6 Sheets-Sheet 5 William fiummerhe H Jan. 1, 1952 w. SUMM'ERBELL 2,530,483

BREECH BLOCK AND FIRING MECHANISM THEREIN Filed Dec. 4, 1946 e Sheets-Sheet 4 v J6, R J5 90 93 62 45 90 4 46 Willi am 51.1mm EPh EU.

Jan. 1, 1952 w. SUMMERBELL 2,580,483

BREECH BLOCK AND FIRING MECHANISM THEREIN 6 Sheets-Sheet 5 TE 1E- 69 Filed Dec. 4, 1946 4 7! I I 95 I I 7 86 W 66 I. I] g 4 9, 871: Z 'i [00 l n 90 9 I r 20 I 30 E; 85 J! 2- r52 37 29* :Fi j l7 ""ILJ grwe/wtm William 5 ummer']: E11

Jan. 1, 1952 v w. SUMM'ERBELL 2,580,483

BREECH BLOCK AND FIRING MECHANISM THEREIN F iled Dec. 4, 1946 6 Sheets-Sheet 6 Willi am fiummer'ha H Patented Jan. 1, 1952 UNITED STATES ATE-NT OFFICE.

BREECH BLOCK AND FIRING THEREIN Application December 4,1946, S'erial No. 713949 (Granted under the act of March '3, 188 3,'-a's amended April 30, 1928; 370*0. G. 757

3 Claims.

The invention described herein may be manufactured by 'or'for the Government for governmental purposes without payment of any royalty thereon.

This invention relates to a new and useful improvement in breech blocks and firing mechanisms therein, and is designed particularly for 3'7 mm. guns. The improved gun has a breech ring containing a sliding breech block and in which is mounted the improved firing mechanism; comprising the firing pin assembly, the cooking lever, and sear. There is also provided an operating lever for the breech block, and cartridge case extractors.

The particularly valuable features of the improved gun. are the roll sear co-acting with a sleeve for the firing pin, the cocking p unger for the cooking lever, the structure, mounting and operation of the lever for sliding the breech block, the structure of the case extractors, and the cylindri al contour of the breech ring, devoid of protrusions, which greatly facilitates its fabrication.

While there has been illustrated in the drawings filed herewith, and hereinafter fully described, cne s ecific embodiment of the invention, it is to be distin tly understood that the invention is not considered to be limited to said specific embodiment, its scope being defined by the claims appended hereto.

In the drawings:

Figure 1 is a fragmentary ton pla n of a gun provided with the mproved breech mechanism, a portion being broken away;

Figure 2 is a fragmentary side elevation of the breech mech nism, from the right side, a portifn being broken away;

Figure 3 is a view similar to Figure 2, from the left side;

Figure 4 is a rear end elevation of the breech mechanism;

Figure 5 is a fragmentary bottomplan of the breech mechanism;

Figure -6 is a side elevation of thesbreech block in closed position, aportion of the breech ring being broken away;

Figure '7 is a fragmentary'sideelevation of the breech block in cocking position;

Figure 8 is a view similar to Figure 6,"the breech block being in. leading position;

Figure 91s an. enlarged vertical section on the line 9-9 of Figure 1, in the direction of the arrows;

Figure -10 isa fragmentary vertical section of 2 the firing mechanism shown in Figure 9, the parts being "in cockedpposition; v

Figure 11 is a view similar to Figure 10, the parts being in'firing position; I

Figure l2'is a detail perspectiveof the bracket for mounting the operating crank;

Figure 13 is a fragmentary vertical section on the line IS -l3 of Figure 1, showing the round chamberedagainst the extractor lips; V

Figure 14 is a view similar to Figure 13 showing the extractor tripped;

Figure 1'5is a perspective of one of the exin'actor's;

Figure 16 is a vertical section on the line i6l6 of Figure 9, in the direction of the arrows;

Figure I7 is a vertical section on the line "-11 of Figure 9, in the direction of the arrows;

Figure '18 is an exploded view of the firing mechanism; I

Figure19 is a perspective of the breech block.

As illustrated in the drawings the improved gun comprises the tube T, breech ring R, breech block 'B' operating lever L (Fig. 1) and firing mechanism M (Fig. 18). The tube Tand ring R' are connected disclosed and cla med in my Patent 2,445,339, dated JulyZO, 1948'. The breech block B is slidable in a cylindrical transverse bore in the ring R from open loading position (Figs. 8 and 14) to closed firing position (Figs. 6 and 9), by the operating lever L journaled in a removable bracket ll (Fig. '12) carried by the ring R. The firing mechanism 'M comprises a cocking .lever operated by reciprocation of the block B, a striker and a trigger-actuated rockable sear.

The breech ring R has a cylindrical socket I in which is seated the rear end 2 of whose rear T, the tube face'3 is extended into the transverse bore 4 of ring R, provided for the sliding block B. The rear apron 5 of ring R has the load 'hole 6 and throat l thereabove (Fig. 9). The ring'R' is provided. in its bottom face forwardly of bore 4 with a plane surface portion 8, a dove-tail socket 9 above and at the rear end ofportion 8, and a concave key-way ID at the forward end of portion 8. A. bracket H isseatedonportionB, its upstanding'dove-tail key [2 being received in socket 9 and its convex key 13 being received in key-way lib Bracket H has a pair of dependin'g'bearing's Hi to journal the operating,.-lever' L and a socket 1 5 to receive a lock pin it passed through portiont oi -ring R to removably afix bracket I! to ring 'R. A bore in a threadless joint as 1, concentric with socket l5, opens through bracket II for insertion of a tool to remove pin l6 to permit separation of the bracket from the ring.

The operating lever L has a rock shaft l8, journaled in bearings M of bracket transverse to the longitudinal axis of ring R. Shaft l8 has a radial crank arm l9 on its end on the right side of ring R. This arm |9 has, on its outer end, an extension 20 normal to arm l9, and provided on its upper end with handle 2| having a spring-pressed pivoted latch 22 co-acting with catch 23 keyed into ring R and having an abutment 24 to limit movement of shaft 8 in one direction. Shaft 8 has a radial finger 25 coacting with socket 26 in ring R (see Figure 8) to limit the movement of shaft |8 in the opposite direction, that is, the direction of movement in which the breechblock is lowered to open position. Shaft l8 has, on its end on the left side of ring R, a removable locking collar 21, Figures 16 and 1'7, with spring retainer ring 28, to removably retain shaft 8 in bearings 4.

The breech block B is cylindrical for sliding movement in bore 4 of ring R. Block B is recessed on its lower right side to provide spaced plane abutments 29 and 30, Figures 6 to 8, with which co-acts off-set lug 3| on the end of arm 32 normal to crank arm 33 radial to and integral with shaft l8. See Figure 16. Rocking of shaft |8 causes lug 3| to bear against abutments 29 and 30 to lower and raise block B, respectively. Block B has an arcuate surface 34 extended upwardly and forwardly from abutment 30, to receive thereon the correspondingly curved face 35 of lug 3| when the block is in fully raised or closed position. The corresponding arcs of surfaces 34 and 35 are concentric with shaft I8. It will be noted (Fig. 6) that when block B is raised, and latch 22 is engaged with catch 23, the arm 32 is vertical, lug 3| bearing on surface 34. Movement of lug 3| along abutment 3U raises block B to closed position and lug 3| moves alon surface 34 without further movement of block B, until arm 32 is vertical, thus providing a mechanical lock for block B.

The firing mechanism M (Fig. 18) is mounted in breech block B. Block B has a diametrical bore comprising four co-axial portions of progressively reduced diameters. The portion 36 situated at the rear of block B has the lar est meter. Portion 31, situated in the middle of block B. has a reduced diameter, forming shoulder 38. Portion 39, extending forwardly from portion 31 has a reduced diameter, forming shoulder 49. Portion 4| extending forwardly from portion 39, has a reduced diameter forming shoulder 42 (Fig. 9). A cylindrical sleeve 43 has a smooth sliding fit in portion 39. Sleeve 43 has a peripheral flange 44, the outside diameter of which is slightly less than that of portion 31 so that flange 44 slides therein. The sleeve 43 has formed on its forward end a barrel 45 provided with a threaded axial bore 46. The barrel 45 is provided on diametrically opposite sides on its outer periphery with cut-away portions 41 forming plane chordal faces 48 with the inner periphery of sleeve 43, forming two segmental passages between the plane surfaces 48 of barrel 45 and the interior of sleeve 43. A bolt 49, disposed in sleeve 43, has its forward end threaded in bore 46 of barrel 45. A lock pin passed through barrel 45 and bolt 49 fixes bolt 49 against axial movement relative to barrel 45. On the forward end of bolt 49, pro- ,jecting from barrel 45. there is a suitable firingpin 4 5| to project through hole 4| of the bore of block B which opens through the forward face of block B as indicated at 52. A collar 53 has its inwardly-flanged rear end loosely fitting bolt 49 rearwardly of barrel 45. The collar is provided with two forward projections 54 passed through the said passages between sleeve 43 and barrel 45, and having plane faces 55 hearing on the plane faces 48 of barrel 45 and arcuate faces 56 corresponding to the curvature of sleeve 43. An expansion spring 51 is confined between head 58 of bolt 49 and collar 53 to urge collar 53 against rear end of barrel 45, that is, the position shown in Figures 9 and 10.

A retainer cap 59 is removably mounted in portion 36 of the bore of block B by a bayonet-joint provided by socketed lugs 60 in the portion 36 in which are seated lugs 6| on the cap 59. Cap 59 has seated therein the firing spring 62 passing through sleeve 43 and about bolt 49, and bearing against collar 53.

The breech block B is provided on its upper right side with a recess 63 at the lower end of which there is a transverse bore 64, below which there is a recess 65 of less depth than the bore 64 and of greater depth than the recess 63. At the bottom of recess 65, there is an arcuate slot 66, Figures 6, '7 and 8, communicating with portion 31 of the axial bore of the block B. A cocking lever 61 (Fig. 18) has its hub 68 journaled in the bore 64, its upper arm 69 received in recess 63 and its lower crank. arm 10 received in recess 65. Arm 10 has an'off-set finger H (see also Fig-. ure 18) extending through slot 66 into the portion 31 of the axial bore of the block B. Lever 61 has a lug 12 projecting from the junction of hub 68 and arm 69 with which co-acts a springpressed plunger 13 slidably mounted in block B, to urge arm 69 into counterclockwise rotation as viewed in Figure 6. Arm 69 has an off-set lug 14 on its upper end. As above mentioned, the cocking lever 61 is automatically actuated by reciprocation of block B. As shown in Figs. 1 and 6, when the block B is raised to closed position, arm 69 of lever 61 is against the rear wall of recess 63, urged thereto by spring-pressed plunger 73, and extends rearwardly over the rear apron 5 of breech ring R. Suitably disposed in ring R below arm 69, when it is thus positioned, there is an inclined cam surface 15 with which lug l4 co-acts to rock arm 69 forwardly or clockwise as block B is lowered. At the forward end of surface '|5, the ring R has a cut-away portion providing a plane vertical dwell surface 16 over which lug 14 travels, holding arm 69 forwardly as the block descends. Ring R is provided with an inclined bore 11 disposed at an acute angle to surface 16. Slidable in this bore 11, there is a springpressed cocking plunger 18 bearing against an abutment 19 partially closing the lower end of bore 11. The remainder of bore 17 opens through surface 16, permitting the lower end of plunger 18 to protrude beyond surface 16. It will be noted (Figs. 6, '7 and 8) that the peripheral cylindrical wall of plunger 78 is so disposed as to form a cam surface for lug 14 to further project arm 69 forwardly (Fig. '7), and that lug |4 riding off of plunger 18 permits arm 69 to move rearwardly to engage lug 14 with surface 16 (Fig. 8). When block B is raised to closed position, it is obvious that lug '|4 engaging the end wall 8| of plunger '|,8'will retract plunger 18 against its spring, lug 14 riding on surface 16.

.The breech block B (Fig. 19) is provided on its left side with a channel or recess 82 extending ascents;

5, from the topo! block: B to'v'a point below. the bottom of the above describedaxial-bore in :block B. At thebottomof recess 82, there is an abutment 83. A recess 8t extendsforwardly in block B, and from recess 8G, a recess 85 extends transversely of block B. From the inner side'of recess 35, a transverse bore .33 extends .into blockB- to a point somewhat beyond the axis of block B. It will be noted (Fig. 16) that bore 88 communicates with portionBl of the axial bore of block B. Block B has a bore 81' extending from. the bottom upwardly to a point above transverse bore 86, and communicating therewith. A transverse bore 88 extends from the left face of block B into the bore 8'! somewhat above bore 35. The sea-r89 (Fig. 18) comprises arock shaft as which is journaled in bore 86 and a crank arm 9! on the left end of shaft Bil and received in recess 85. The arm 9| has on its outer end an off-set lug 92 received in. recess 84. The shaft to is cutaway on its right end to provide a plane face 93, and is notched in its portion disposed across the bore 81 to provide a plane face 9 A plunger 95 disposed in bore 81 bears against one end of face 94 eccentric to axis of shaft 95, so that shaft so is biased by spring 96 disposed between plunger 95 and end of bore 81. Plunger 95 has an annular groove 91.

The breech ring R has a slot 98 (Figure 1) from its left side extending into its bore i. Suitably pivoted in this slot 98, there is a trigger as having an operating ring is!) on its outer end extending outwardly from ring and a finger ill! on its inner end and extending into bore i and receivedin recess 82 of breech block B. This finger ml co-acts with lug 92 of the sear as, when .trigger 89 is roo -ed to proiect finger is! forwardly from recess 32 into recess 35. causing lug '92! to rotate clockwise as seen in Figure 18 and. through crank arm 3|, rock shaft A spring-pressed plunger m2 mounted in ring R bears against a lug I Eli-i to press trigger iii! a ainst abutment H34 at the forward end of slot 93. It will be noted (Fig. 1) that when trigger at is seated against abutment I 64, the finger lill disposed in recess 82 of block 13, and that conseouently it serves as a stop pin for abutment 83 at the lower end of recess 82 to limit the movement of blockB upwardly into closed posi-- tion.

Asclearly shown inFig 9, the peripheral flange of sleeve 43 inv the axial bore of block B has a forward end face Ma lying in a plane normal to sleeve 53 and provided with an outer peripheral convex fillet Mb. The rear end face Me of collar dd tapers rearwardly to form a cam surface to co-act with plane face 93 of scar 8.5-3. As clearly shown in' Fig. 16, the off-set finger H of cooking lever 61 is disposed to bear against radial face Add to retract sleeve 43 when lever 61 is rocked. It will be noted (Fig. 19) that the plane faces 93 and E i of scar 89ers angularly disposed, so that bolt 55 bearing onface fie tends to bias sear 83 to position face 93 to receive earn face ite when sleeve as is retracted by lever El, and that when collar it has moved rearw-ardly over the rear edge of face 9-3, the sear 89, rocked by bolt 95 pressing on face 9 moves into the position shown at Figure 10 and locks sleeve A3 in cocked position. It is obvious, that when sear 89 is rocked by trigger 99, as above described, its arcuate portion is withdrawn from fillet 5th, and its plane face 93 being disposed on the periphery of portion 31 of the axial bore of the block B, sleeve 43 is released.

a will be noted: (Fig. .18) that sear arms-a:

notch tfla disposed in the rear edge of face-.93;

A pair of extractors .l 05, one-of which is shown in: Figure 15,, are mounted in ring R and .are

automatically operated by reciprocation of block- B. Each extractor I05 comprisesa trunnionlllfi,

an upstanding lever arm ml carrying an off-set finger Hi8, and a depending crank arm lllil with a rearwardly turned toe Ht. Thetrunnions Hi6 are .journaled in bores IH suitably positioned in the ring R, and the extractors 55 are disposed in channels formed by recesses H2 on the forward sides of block B, their fingers H18 seated in sockets H3 symmetrically disposed, in tube face 3, on diametrically opposite sides of its axis. Ht, at the rear of recesses H2, co-acting with toes N9 of the extractors "F5 to actuatesame BlockB is provided in its top with. a concave. channel H5 corresponding in curvature. with.

load hole.6 of ring R. At the forward edge of channel H5, block B has abevelled edge H6 sloping downwardly to the upper edge of an In firing a round, assuming the gun to have an empty shell therein, and the breechblock in upper, or closed position, lever L is grasped, released by pressure on latch 2'2 to free it from catch 23, and swung counterclockwise as viewed in Figure 2. This pivotal movement first causes lug 3! to traverse arcuate surface, Figure 6, to unlock the breechblock. Thereafter, the lug engages abutment 29 and positively lowers the block in timed relation with pivoting of the lever.

As the breechblock descends, cam surfaces H4 thereon engage the toes Ill] of the respective extractors I05 and pivot the extractors counterclockwise, from the position shown in Figure 13 to that shown in Figure 14. causes fingers H88 to force the empty shell out of the breech chamber with momentum sufficient to throw it clear of the breech as the block moves to fully open position.

As the breechblcck begins to lower, lug 14 of cocking lever 61-, first rides on inclined cam surface 75 and is thereby pivoted clockwise from the position seen in Figure 6 to that shown in Fi-ure 7. This pivotal movement includes a small additional increment as lug M rides over the projecting end 8! of plunger 18. The total movement is sufficient to cause lug H (Figures 16 and:

18), of cooking lever 6'! to engage face Ma of flange 44, and force sleeve 43 rearwardly, against the action of spring 62. As thesleeve moves rearwardly in bore 31,, the rearward cam face 440 of flange 44 engages the .fiat surface 9311f sear...

89, which is in: the approximate inclined -posi-' tion shown at Figure 9, and pivots the sear shaft 9i counterclockwise'as seen in that figure, against the yielding action of plunger and its spring 96 until, as the flange clears shaft 93 in the continuedrearward motion of sleeve 43, the shaft is released and, under the urge of spring 96 and plunger 95, pivots clockwise to the position shown in Figure 10, thereby locking the sleeve and firing pin assembly in cocked position. When the breechblock is in fully lowered or opened posi- Eloclr B is provided with suitable-cams This movement,

tion lever 61 is in the position shown in Figure 8 and its lug '14,- in conjunction with spring-urged plunger 18, acts to yieldingly hold the breechblock in open position. As the breechblock is lowered the shoulder of recess 82 moves opposite and engages trigger 99 to lock it against pivotal movement, as is obvious from inspection of Figure 1.

A round of ammunition is now chambered in the usual manner until its rim engages the fingers I08 of extractors I05, which are in the position shown at Figure 14. Lever 2! is next rotated from the position of Figure 8 to that of Figure 6, to close the breechblock. At the beginning of closure lug 14 of cocking lever 01, cams plunger 80 inwardly and, as the block closes, returns to the pivotal position of Figure 6 under the urge of plunger 73. When the block B is fully closed, it is locked in this position by the mating surfaces 34 and 35 as is clear from Figure 6. Lever L is at this time latched in position by parts 22, 23, as seen in Figure 2. Also, at this time, finger [01 of trigger 99, is within recess 85 of block 13 (see Figure 19), and is thus freed for firing movement.

To fire the gun, trigger 99 is pivoted counterclockwise from the position of Figure 1. Finger |l then engages lug 92 of sear 89 and pivots sear shaft 90 counterclockwise from the position shown in Figure 10 until sleeve 43 is released and spring 02 drives the firing pin assembly forwardly. As the assembly moves forwardly, the ends of fingers 54 of collar 53, strike the forward end of bore 39, as seen in Figure 9, and arrest further movement thereof. The momentum of firing pin 49 then carries the pin forwardly, against the thrust of spring 51 until the tip projects through hole 52 (Figure 19), in block B, and detonates the primer of the chambered round. Projection of tip 5| is limited to the amount shown at Figure 11, by engagement of the forward face 44a of flange 44, with shoulder 40. After firing, the pin is immediately retracted to the position shown at Figure 9, within the block B, by the action of spring 51. The block is now ready to be lowered for the next round.

I have thus provided a breechblock and firing mechanism which is positive in action, simple to operate, and easily assembled, disassembled, adjusted and repaired. While I have shown the preferred form of the invention, numerous modifications will occur to those skilled in the art, after a study of the foregoing specification. I therefore desire that the disclosure be taken in an illustrative rather than a limiting sense; and it is my desire and intention to reserve all those modifications falling within the scope of the subjoined claims.

Having described the invention, what I claim is:

1. In a firing mechanism for a gun, the combination of a firing pin reciprocable in the gun; a rock shaft transverse to said pin in the gun, said shaft having a cut-out portion forming a plane face and a notched portion forming a second plane face, said faces lying in planes describing chords of the circumference of the shaft, respectively; a spring-pressed plunger bearing on the said face of the notched portion, eccentric to the axis of the shaft, tending to bias the shaft to intrude the said face of the cut-out portion into the path of said pin; means to reciprocate said pin to cooking position; a cam shoulder on said pin co-acting with said intruded face to rock said shaft, when said pin is reciprocated, said plunger rocking said shaft to engage said shoulder when said pin is cooked; a crank-arm on said shaft; a trigger pivoted on the gun for swinging said arm to rock said shaft against the force of said plunger, to release said shoulder and said firing pin; and resilient means in said gun associated with said pin and energized by the reciprocation of the pin, and projecting the pin to firing position when the shoulder is released by the trigger action.

2. In a gun, the combination of a breech block; a firing pin reciprocable in and projectable from said block; a peripheral flange mounted on said pin and having a forward face normal to the axis of the pin and a rear face inclined rearwardly at an acute angle to said axis; a finger pivoted in said block for engagement with said forward face; means in said block for rocking said finger to retract said pin into cocked position; a sear rockably mounted in said block in the path of said flange, said rear face camming said scar on retraction, and the sear engaging said forward face after retraction to hold said pin cocked; manual means for rocking said sear.

to release said pin; and means to project said pin from the block into firing position when the pin is released.

3. In a gun, the combination of a breech block provided with an axial bore therethrough; a sleeve slidable in said bore; a peripheral flange on said sleeve having a forward face normal to the axis of the bore, and a rear face inclined rearwardly at an acute angle to said axis; a firing pin mounted in said sleeve; a retainer cap removably mounted in said bore; an expansion spring confined between said sleeve and said cap; a reciprocable finger in said bore forwardly of said flange; means in said block to reciprocate said finger to engage the forward face of said flange, retracting said sleeve to compress said spring to cook said firing pin; a sear rockably mounted in said block and resiliently intruded into said bore rearwardly of said flange prior to said retraction, the said inclined face camming the scar on said retraction and the sear engaging the said forward face after said retraction; and manual means for rocking said sear to release said sleeve, said spring projecting the firing pin into firing position.

WILLIAM SUMMERBELL.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 718,719 Meigs et a1 Jan. 20, 1903 784,362 Tasker Mar. 7, 1905 798,882 Dearborn Sept. 5, 1905 1,072,456 Hermsdorf Sept. 9, 1913 1,393,353 Driggs Oct. 11, 1921 2,245,621 Summerbell June 17, 1941 2,245,623 Summerbell June 17, 1941 2,279,352 Summerbell Apr. 14, 1942 2,398,453 Summerbell Apr. 16, 1946 

